System and method for providing an improved terrestrial subsystem for use in mobile satellite systems

Abstract

A system or method is disclosed which employs filters on a satellite whose bandwidth is varied by ground command to restrict interference experienced by a satellite as an auxiliary terrestrial component (ATC) system is increased to a multiplicity of cities and markets. Thus there is provided a novel method and system which optimizes overall MSS and ATC traffic.

Description

I. FIELD OF THE INVENTION[0001]The present invention relates to satellite radio telephone systems and methods. More specifically, the present invention relates to mobile satellite systems employing an augmented terrestrial component.II. BACKGROUND OF THE INVENTION[0002]It is known that satellite radio telephones have been developed and deployed throughout the world, especially where topographical conditions preclude use of conventional mobile radio telephones or fixed wire telephones, for example in rugged terrain areas or sparsely populated areas. These systems typically are understood to provide both voice and data communications so that they may include terminals such as PCS terminals.[0003]Prior art satellite radio telephone systems may be broadly classified into two types: mobile satellite radio telephone systems and fixed satellite radio telephone systems. In each of these systems one or more satellites are used to communicate with radio telephones, the satellites being either...

AI Technical Summary

Benefits of technology

[0020]It is therefore an object of this invention to provide a satellite terrestrial communication system and method of operation that facilitates effective spectrum assignment, usage sharing and / or reuse.

[0021]A further object of this invention is to provide a satellite terrestrial communication system and method of operation thereof that minimizes interference between the satellite and terrestrial systems.

[0023]Again another object of this invention is to provide a satellite terrestrial communication system and method that enables a terrestrial underlay system associated with a first area of coverage to reuse and / or share in a substantially central portion thereof at least a portion of the frequency spectrum of one or more adjacent areas of coverage of the satellite system.

[0028]Yet again another object of this invention is to provide a satellite terrestrial communication system and method of operation that minimizes interference between the satellite and terrestrial components.IV. BRIEF SUMMARY OF THE INVENTION

Problems solved by technology

Generally, the per-satellite capacity of a satellite radio telephone is limited by the amount of satellite power that is expended per communication circuit in order to establish and maintain communications with a radio telephone.

In addition, limiting factors such as available frequency spectrum and the typically poor frequency reuse of satellite radio telephone systems impact the per-satellite capacity of these phones.

Consequently, mobile satellite radio telephone systems have been found to generally possess much lower capacity than fixed satellite radio telephone systems.

Both regional and global mobile satellite systems are found to be quite limited in capacity, the regional mobile satellite systems involving geostationary satellites having, for example, a capacity per satellite of about 10,000 simultaneous voice circuits, whereas global mobile satellite systems involving both medium earth orbiting satellites, or MEOs, or low earth orbiting satellites, or LEOs, generally have even lower capacity per satellite ranging into the 3,000-4,000 simultaneous voice circuits.

The practical limitations involved in forming a very large number of spot beams from the satellite often limits frequency reuse for mobile satellite radio telephone systems resulting in generally low capacities of said systems.

Prior art methods to increase the relatively limited capacity of mobile satellite radio telephone systems experiencing capacity bottlenecks or hot spots which are developed in congested areas of the mobile satellite radio telephone system where the mobile satellite radio telephone system (MSS) does not have enough capacity to accommodate all users, it is found difficult to increase the capacity of the MSS in these congested areas.

Difficulty is experienced for cellular satellite communication systems to reliably serve densely populated areas where the satellite signal may be blocked by high rise structures or may not penetrate into buildings.

In such cases, the satellite spectrum may be underutilized or unutilized in such areas.

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